Nationwide
A high-pressure ridge continued across the southern Plains during this U.S. Drought Monitor (USDM) week (August 14-20), bringing dry and very hot weather, especially to Texas.
Pacific weather systems moving in the jet-stream flow brought above-normal precipitation to parts of the West Coast, the northern to central Rockies, and parts of the central to northern Plains, the Midwest, and the Northeast. The rain was frequently hit-or-miss, with large parts of the Pacific Northwest to Plains, and Midwest to Northeast, receiving little to no precipitation. In addition, much of the Southwest and southern Plains to Southeast were drier than normal this week.
An upper-level trough kept the Far West cooler than normal, while a large cold front brought cooler-than-normal temperatures to much of the Midwest to the East Coast. The rain contracted drought and abnormal dryness in parts of the Rockies to the central Plains and a few parts of the Midwest and East Coast. However, drought or abnormal dryness expanded or intensified in parts of the West that missed out on the precipitation, parts of the Great Plains, from the Tennessee Valley to the Central Gulf of Mexico coast, and parts of the Midwest to the Central Appalachians.
The lack of rain continued to dry out soils across large parts of the West (especially the Pacific Northwest), the southern Plains, the Lower Mississippi Valley, and the central Appalachians. Numerous wildfires were burning across the West, with some sparking up in the southern Plains and western High Plains. The most severe drought areas included the central Appalachians, the Upper Ohio River Valley, the Rio Grande River Valley, eastern Wyoming, western Montana, and central Washington.
The West
Half an inch of rain or more fell this week along the Washington and Oregon coast, in the Rockies, and parts of the Southwest (Four Corners States), with little to no rain falling across most of California, Nevada, and interior portions of the Pacific Northwest.
Temperatures were cooler than normal in the Far West to Great Basin, averaging as low as 4-6 degrees below normal, but warmer than normal in southern and eastern areas, averaging 2 to locally 8 degrees above normal in Arizona, New Mexico, and Montana. Contraction of abnormal dryness or drought occurred in a few parts of New Mexico, Utah, and Montana, but drought or abnormal dryness expanded in the Pacific Northwest, California, and Nevada. The most notable changes occurred in Washington and Oregon, where moderate to severe drought expanded.
More than 60% of the topsoil/subsoil moisture was rated short or very short in Oregon (81%/75%), Washington (69%/65%), Idaho (65%/62%), Montana (78%/79%), and New Mexico (70%/70%). Almost two-thirds of the pasture and rangeland was rated in poor to very poor condition in Oregon (62%) and Washington (63%).
The High Plains
Like other parts of the country, the High Plains region experienced wet and dry periods this week.
Weekly rainfall totals ranged from zero in parts of Wyoming to locally over 2 inches in the Dakotas, Nebraska, and Kansas. Eastern parts of the Dakotas and Nebraska averaged near to cooler than normal for the week, but areas to the west and south were warmer than normal, with some areas 2-4 degrees above normal.
There was an expansion of drought and abnormal dryness in most states in the region, more in the north, and a contraction in primarily southern states. The more notable changes were the expansion of moderate to severe drought in Kansas and Wyoming, with extreme drought being introduced in Wyoming and adjacent South Dakota, and the contraction of abnormal dryness and drought in Colorado and Kansas, especially southeast Kansas, where locally up to 5 inches of rain fell.
Reports of significant hay loss and early cattle sales in South Dakota may be due to a combination of drought and a June 19 freeze event; other drought impacts include surface water shortage and poor water quality for livestock. According to USDA reports, in Wyoming, 75% of the topsoil moisture and 81% of the subsoil moisture are short or very short, and 66% of the pasture and rangeland are rated as poor or very poor. More than 40% of the topsoil moisture was short or very short in Nebraska, Colorado, and Kansas, with 55% of the subsoil moisture so rated in Kansas.
The South
The keywords for the South region are hot and dry.
Most of the region was warmer than normal, with only eastern Tennessee near normal. Parts of northern Texas had weekly temperatures 6 to 10 degrees above normal, with daily high temperatures over 100 F all week and exceeding 110 on some days. Parts of Arkansas and eastern Oklahoma received over 2 inches of rain this week, with locally over 5 inches, and there was a smattering of showers in Louisiana, Mississippi, and Tennessee, with rainfall mostly half an inch or less. Texas and most of Oklahoma received little to no rain this week. With dry soils, high evaporation, and deficient rainfall, abnormal dryness expanded in parts of most of the South region states.
Moderate drought expanded in Texas, especially in north central Texas, where the fire danger was high and several large wildfires were burning; extreme drought expanded in the Texas Trans Pecos. Moderate to severe drought expanded in Oklahoma, Mississippi, and Tennessee. Abnormal dryness and moderate drought were trimmed where the heaviest rains fell in eastern Oklahoma and western Arkansas.
Soils were very dry: USDA topsoil/subsoil percentages short or very short include 75%/65% for Texas, 65%/50% for Louisiana, 62%/59% for Mississippi, 53%/49% for Arkansas, 50%/52% for Tennessee, and 47%/49% for Oklahoma. Mississippi experienced a 70% loss of field corn in the east-central portion of the state during the mid-June through early July dry period. Extension agents are reporting a likely significant loss of cotton and soybeans in this region as well. — UNL Drought Monitor
